Pfft! She doesn't have several different "Hit Harder" Actions and has some synergy in her Perks and Actions, both of which a good chunk of the PCs lack so no, she's not bad at all.
Formless Form Fatale: Needs to scale.
Passion-Lip's Love: Soul-Crushing Ten-bladed Embrace: Huh, that's interesting, a Basic Attack leveled up to the point of being a decent primary attack method. More people ought to do this seeing as it saves them an Action Slot. Especially people whose attacks are expressed in terms of their Basic Attack. The multi-targeting overlaps with
All Embracing Goddess though, making it pointless to multi-target unless there are more than three foes.
The Soft Grasp of a Mother's Warmth: Huh, guess we actually do have someone able to heal multiple people decently. Again, thanks to
All Embracing Goddess. The boost's also nice.
A Sweet Lullaby Sung to a Restless Child: Why is Stun, something that one could reasonably expect most Bosses and Minibosses to resist or negate, the go-to choice of Status Effect? Yes it's balanced, I can tell because so many people have this exact same Action just with different flavoring. Look into other options, such as lowering their rolls from sleepiness, or making them so lethargic that whoever they target has an increased chance on using an on-attack effect (such as counterattacking, blocking on reaction, dodging, etc).
Taunt to the Shadows with the Immovability of Light: Sort of iffy that having a higher INT stat makes a foe more vulnerable. But that doesn't really matter since only something with 4 or less INT will be able to resist, and
Flare with the Awe of Greater Creation will easily cover them.
So, a Support/Tank.
Detached From This Plane Of Existence makes it harder to judge. A bit messed up in that its got better attack-drawing capabilities than basically all the other tankier characters other than Yuki, who isn't even a PC. Let's see, I suggest she learns how to play American Football or otherwise work with Aesford more, because
Flare with the Awe of Greater Creation and
Brilliance of a Star Burning Upon The Earth works very well with
Interception. If you do upgrade
Flare with the Awe of Greater Creation, a damage reduction bonus, or being able to autocast
Light Barrier as a Free Action upon use ought to make it safer to use.
As for progression, not too sure, perhaps give
Passion-Lip's Love: Soul-Crushing Ten-bladed Embrace a chance to autocast
A Sweet Lullaby Sung to a Restless Child (perhaps with the chance rising with the added SYN damage, to encourage continuous hugs)? That gives some synergy between the two. Oh and to boost the already good synergy between
Taunt to the Shadows with the Immovability of Light and
Flare with the Awe of Greater Creation, see if you can't upgrade the former's effect to stack (maybe with diminishing returns) that way drawing aggro from everyone just ends up with them really demoralized.
She is really, really weird in that her Actions are pretty effective even though she has 5 unspent Action Points. Seriously.
What, Twi? Thought I was going to berate you for not using her Perks? Nope! I'll just badger you to spend all that unallocated AP!